To test the effectiveness of a combination of the investigational drug, Nal-Glu GnRH antagonist, plus testosterone ananthate (TE) as a potential male contraceptive regimen in healthy young men. Specifically, we would like to determine whether this combination of drugs suppresses sperm counts to azoospermia or to severe oligospermia more quickly and in a greater percentage of men than does TE given by itself. We are also testing the possibility that if a man's sperm production is severely suppressed by these two drugs, then the suppression of his sperm count will be maintained by continuing injection of TE by itself.